Main Hawaiian Islands - NCEAS

Main Hawaiian Islands

The State of Coral Reef Ecosystems of the Main Hawaiian Islands Alan Friedlander1,2, Greta Aeby3, Eric Brown3,4, Athline Clark3, Steve Coles5, Steve Dollar6, Cindy Hunter6, Paul Jokiel6, Jennifer Smith6, Bill Walsh3, Ivor Williams3,7, Wendy Wiltse8. Additional Contributions Leon Hallacher6, Carey Morishige3,9, Christine Woolaway10, Thierry Work11, Francis Oishi3, Brian Tissot12

INTRODUCTION AND SETTING

Hawaii is one of the most isolated archipelagos in the world and as a result, possesses some of the highest marine endemism recorded anywhere on earth. Because they are located in the middle of the Pacific Ocean, Hawaii’s coral reefs are exposed to large open ocean swells and strong tradewinds that have a major impact on the structure of these coral reef communities. The archipelago consists of two regions: the Main Hawaiian Islands (MHI) which consists of populated, high volcanic islands with non-structural reef communities and fringing reefs abutting the shore (Figure 9.1), and the Northwestern Hawaiian Islands (NWHI) consisting of mostly uninhabited atolls and banks which are the subject of a separate chapter. This island chain stretches for over 2,500 km from the island of Hawaii in the southeast to Kure Atoll (the world’s highest atoll latitudinally) in the northwest. Coral reefs were important to the ancient Hawaiians for subsistence, culture, and survival. According to the Hawaiian Creation Chant, the kumulipo, the coral polyp was the first creature to emerge from the sea during creation. The early Hawaiians recognized that coral reefs were a building block of the islands and used coral in religious ceremonies to honor and care for ocean resources. Today, Hawaii’s coral reef communities provide protection from storm waves, create the large surf that makes Hawaii world famous, provide food for sustenance, and are critically important to the State’s approximately $800 million per year marine tourism industry. Over 70% of the state’s 1.2 million people live on Oahu, and are mostly concentrated in the Honolulu metropolitan area. In addition to the resident population, nearly seven million tourists visit Hawaii each year. This concentrated number of people has put pressure on Hawaii’s coral reefs through various direct and indirect means. In general, Hawaii’s coral reefs are in better condition than many other reefs around the world, although urban areas and embayments have suffered from land-based sources of pollution, overfishing, recreational overuse, and alien and invasive species.

1 NOAA/ NOS/ NCCOS/ Center for Coastal Monitoring and Assessment, Biogeography Program. 2 Oceanic Institute 3 Hawaii Department of Land and Natural Resources, Division of Aquatic Resources 4 National Park Service 5 Bishop Museum 6 University of Hawaii 7 Hawaii Coral Reef Initiative 8 Environmental Protection Agency 9 NOAA/NOS/ Hawaiian Islands Humpback Whale National Marine Sanctuary 10 Hawaii Sea Grant Program 11 U.S. Geological Survey 12 Washington State University page 222

Main Hawaiian Islands Sidebar

The State of Coral Reef Ecosystems of the Main Hawaiian Islands

Figure 9.1. Maps of the MHI showing locations mentioned in this chapter. Map: A. Shapiro. page 223



ENVIRONMENTAL AND ANTHROPOGENIC STRESSORS Climate Change and Coral Bleaching Hawaiian waters show a trend of increasing temperature over the past several decades (Figure 9.2) that is consistent with observations in other coral reef areas of the world (Coles and Brown, 2003). The first documented multi-locational coral bleaching occurred in Hawaii in late summer of 1996, with a second event in 2002 (Jokiel and Brown, 2004). Although bleaching events may have occurred prior to 1996, there is no quantitative or qualitative record of previous episodes. These documented bleaching events in Hawaii were triggered by a prolonged regional positive oceanic sea surface temperature anomaly greater than 1°C that developed offshore during the time of the an- Figure 9.2. Weekly averaged points for NOAA Fisheries temperature series taken nual summer temperature maximum. at Koko Head, Oahu (21°17’N, 157°41’W) and weekly IGOSS-NMC data series that overlapped temporarily. Data sets were merged. Source: Jokiel and Brown, 2004. High solar energy input and low winds further elevated inshore water temperatures by 1-2°C in reef areas with restricted water circulation (e.g., Kaneohe Bay, Oahu) and in areas where mesoscale eddies retain water masses close to shore for prolonged periods of time (Figure 9.3). Bleaching was recorded throughout the State of Hawaii in 1996, with the most severe impact observed on Oahu and lesser bleaching reported on Maui and Hawaii. On Maui, weekly temperatures on reefs at eight locations on the southwest coastline showed a range of 28.0-28.5°C in late August and early September, with peak temperatures approaching 29°C. Corals began to bleach at Olowalu, Maui in late August, but the extent and severity of bleaching was minor, with less than 10% of the corals being affected. Recovery occurred after several months. The second major bleaching event in the NWHI transpired during the summer of 2002 (Aeby et al., 2003). A detailed description of this event is provided in the chapter on the NWHI’s coral reef ecosystems.

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Figure 9.3. Map of Kaneohe Bay, Oahu. Shaded area shows reef areas with a high proportion of bleached corals (>20%) on 31 August 1996. Pie charts show relative portions of bleached, pale and normal coral coverage on transects located throughout Kaneohe Bay at that time. Source: Jokiel and Brown, 2004.

Diseases Coral populations in the Hawaiian Archipelago continue to be spared from epidemic disease outbreaks unlike many other corals reefs around the world. Baseline surveys for coral disease were recently conducted at 18 sites around Oahu. The average prevalence of disease (no. diseased colonies/total no. colonies) was estimated at 0.95% (range 0-4.4%). Differences in disease prevalence were found among coral genera, with Porites having the highest prevalence of disease. The most common condition found on Porites was growth anomalies or ‘tumors’ (Figure 9.4). Prior studies found growth anomalies on Porites from both Oahu and Hawaii Island (Hunter, 1999; Work and Rameyer, 2001). Similar growth anomalies have not yet been documented on Porites in the NWHI despite intensive coral disease surveys (Aeby, unpublished data). The cause of Porites tumors has not yet been elucidated, but the occurrence of tumors on Porites lobata is positively correlated with colony size (a broadly generalized proxy for colony age; Hunter, 1999). Another common disease found in both the MHI and NWHI is Porites trematodiasis caused by the larval stage of the digenetic trematode, Podocotyloides stenometra (Aeby, 1998; Figure 9.4). The greatest abundance of infected coral has been found on the reefs in Kaneohe Bay on the windward side of Oahu (Aeby, 2003). In Kaneohe Bay, infected corals have been found in all reef zones from the reef flat to the bottom of the reef slope and have persisted on the reefs since the 1970s (Cheng and Wong, 1974; Aeby, 2003). Trematode infection can cause reductions in coral growth of up to 50% (Aeby, 1992).



General coral necroses also commonly occur on Hawaiian reefs. Hunter (1999) found that necrotic patches followed one of three outcomes: 1) complete recovery, 2) successional change from turf to crustose coralline algae on which new coral recruits become established, or 3) persistence of the turf community with a net loss of coral cover. No major die-off of corals has ever been documented due to disease in Hawaii. However, increasing human usage and the impacts of global climate change are causing concern about the health of Hawaiian reefs. Plans are currently underway to extend baseline disease surveys out to the MHI. The Hawaii Department of Land and Natural Resources - Division of Aquatic Resources (DAR) will also be integrating coral disease assessment into its monitoring program. The endangered Hawaiian green sea turtle is affected by fibropapillomatosis (FP), a disease that causes external and internal tumors in turtles. Turtles with FP also have significant additional complications including inflammation with vascular flukes, bacterial infections, poor body condition, and necrosis of salt gland (Work et al., in press). Recent evidence suggests the herpes virus as a probable cause or co-factor of FP (Herbst, 1995). In Hawaii, FP has been found in 40-60% of observed turtles, with juvenile turtles constituting most of the cases (Balazs and Pooley, 1991). A recent study found that the majority of stranded turtles were juvenile turtles affected by FP and suggested that FP may detrimentally affect survival in juveniles (Work et al., in press).

Figure 9.4. Left panel shows Porites lobata with tumor. Right panel shows Porites compressa with Trematodiasis. Swollen, pink nodules on the coral colony indicate polyps infected with the trematode. Photos: G. Aeby. page 225



As such, FP may pose a significant threat to the long-term survival of the species (Quackenbush et al., 2001). Tropical Storms By virtue of its isolation, the structure of Hawaiian reefs is molded by a unique set of biogeographical factors and physiological tolerances which limit community assemblages to a relatively few hearty species. Another unique aspect of the geographical location of Hawaii is direct exposure to long-period swells emanating from winter storms in both the northern and southern hemispheres (Figure 9.5). Breaking waves from surf generated by Pacific storms is the single most important factor in determining Figure 9.5. Large winter swells, such as this in Peahi, Maui, impact the structure of the community structure and compo- coral reef communities in Hawaii. Photo: E. Brown. sition of exposed reef communities throughout the MHI (Dollar, 1982; Dollar and Tribble, 1993; Dollar and Grigg, 2004; Jokiel et al., 2004). The exception to this general rule is sheltered embayments that make up less than 5% of the coastal areas of the MHI. Hawaiian coral community structure has been shown to respond to storm wave stresses of varying frequency and intensity as described by the ‘intermediate disturbance hypothesis’ (Grigg, 1983). Moderate cover and peak diversity is attained as the result of a continual cycle of intermediate intensity disturbances. High coral cover with low species diversity is found in sheltered embayments and areas protected from direct swells (e.g. south Molokai). Based on the structure of coral communities on dated lava flows on the island of Hawaii, it has been projected that it takes about 50 years for Hawaiian reefs to regain peak diversity following a catastrophic event (Grigg and Maragos, 1974). A 30-year study documenting the impacts of storm waves of varying intensity on the west coast of the island of Hawaii has shown that shallow zones, populated primarily by a pioneering species of cauliflower coral, recovered completely within 20 years to pre-storm conditions, while deep reef slope zones showed only the initial stages of recovery during the same period. In addition, the study showed that recovery might not always result in immediate replacement of the same dominant species in a particular zone (Dollar, 1982; Dollar and Tribble, 1993; Dollar, 2004). The cycle of repetitive impact and recovery is also a major factor in the present-day lack of reef accretion in exposed areas throughout the Hawaiian Islands. Extensive pre-Holocene (last major glacial epoch, approximately 11,000 years ago) reefs have been noted throughout the Hawaiian chain. This may be due to greater storm wave intensity now relative to earlier periods (Rooney et al., 2004), or an increased resistance of preHolocene Hawaiian coral communities to such storms, possibly through species components more adapted to rapid recovery (Dollar and Tribble, 1993). As a result, the only reef accretion that is presently taking place in Hawaii occurs in sheltered embayments or inside barrier reefs that are protected from storm wave impact. A good understanding of the response of reef systems to natural stresses is an important aspect in evaluating the effects of human activities because responses of reef ecosystems to human-induced stress are superimposed on natural cycles of impact and recovery. The few studies in Hawaii to date that examined the effects of storms on fishes show that surf height and degree of wave exposure have negative relationships with various measures of fish assemblage organiza-

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Large storms and typhoons can also affect local fisheries by damaging essential fish habitat (Figure 9.6). In recent decades, two major hurricanes (Hurricane Iwa, 1982; Hurricane Iniki, 1992) struck the islands and caused considerable coral and habitat damage on Oahu and Kauai (W. Aila, pers. comm.). Hurricane Iwa damaged extensive inshore reef areas, especially the prime aquarium fishing grounds along Oahu’s western and southern coast (DLNR-DAR, undated; Pfeffer and Tribble, 1985). Hurrincane Iniki also impacted coral reef communities on Oahu (Brock, 1996; Coles and Brown, in prep.), but limited evidence suggests the effects may have been less than with Iwa (Miyasaka, 1994a, b). Fish catch and value declined around Oahu after the hurricanes but rebounded somewhat in the following years (Walsh et al., 2004; Figure 9.7). With the loss of collecting habitat, collectors concentrated their efforts on those sites still relatively intact and economically viable. The net result of storm effects, when combined with overfishing, was a drastic long-term decline in the abundance of key targeted species such as yellow tangs (Zebrasoma flavescens) around Oahu (Figure 9.7).


tion (Friedlander and Parrish, 1998a; Friedlander et al., 2003). This relationship suggests that habitats protected from the highest wave energies maintain larger fish populations with greater richness and diversity of species. Walsh (1983) found that the impacts on the fish assemblage following a large “kona” storm were ameliorated by the presence of deeper water refuges.

Figure 9.6. A map showing the paths and intensities of tropical storms passing near the MHI from 1979-2004. Year of storm, storm name and storm strength on the Saffir-Simpson scale (H1-5) are indicated for each. Map: A. Shapiro. Source: NOAA Coastal Services Center.

Figure 9.7. Value (adjusted for inflation) of all aquarium fish caught on Oahu and number of yellow tangs caught in primary collecting areas of south and west Oahu. Dashed lines indicate year of major storms. Source: Walsh et al., 2004.

Coastal Development and Runoff Coastlines of Hawaii continue to be developed for a variety of land uses. On all of the islands, agricultural lands (primarily for sugarcane and pineapple) are changing to residential and resort uses. Coastal development can bring a suite of social and environmental consequences including conflicts over shoreline access and viewplanes, the need for flood water storage and protection, infrastructure demands, and degradation page 227



of coastal waters from cumulative increases in runoff and groundwater contamination. Changes in land use from large-scale agriculture, which periodically exposes land to erosion, may result in an overall decrease in sediment delivery to the ocean. Many of Hawaii’s low-lying coastal areas were once wetlands and flood plains before being altered for agriculture and development. These areas served as excellent filters, removing sediments and nutrients from streams before the water entered the ocean. Development inevitably increases the amount of impervious surface and runoff. Runoff is gen- Figure 9.8. This steep roadcut at a construction site on Kauai is vulnerable to eroerally diverted to storm drain sys- sion and movement of sediments to the beach and nearby coral reef ecosystems. tems that, like underground rivers, Practices to stabilize the slope include terracing, erosion control matting, hydromulch, and wattles. Photo: W. Wiltse. transport trash, soil, pathogens, and chemical pollutants to Hawaii’s streams and coastal waters (Figure 9.8). As coastal areas are developed, floodplains filled, storm drains constructed, and streams channelized, more sediment is delivered to nearshore waters. For example, Kulanihakoi Stream (Kihei, Maui) was recently channelized near the shoreline as part of a condominium development, removing a coastal wetland that flooded regularly. The new stream channel solved the flooding problem but increased turbidity in coastal waters has resulted. Harbor facilities on all the MHI are being improved to accommodate new large cruise ships, an inter-island car/ cargo ferry, and large container ships. Harbor improvements involve dredging to deepen and widen entrance channels and turning basins, as well as construction of new piers, waterfront work areas, jetties, and breakwalls. The harbor improvements have the potential to impact coral reefs and areas used for recreation, such as surfing and canoeing. Proposed expansions can affect longshore transport and water quality as well. In Kahalui Harbor on Maui, the proposed development and expansion of pier space to accommodate cruise ships may result in displacement of several canoe teams from the harbor, due in part to the added security zones that would also be designated with the expansion and the resulting lack of protected water area for paddling. At Maalaea Harbor on Maui, a $10 million expansion of berthing facilities and reconfiguration of the entrance channel has been planned for 40 years. The preferred design is controversial because it will eliminate 4 acres of coral reef and impact a surf site, while providing over 100 new berths for recreational and commercial boats. No new construction or approval of permits has been considered to date with this proposed project due to the fact that the impacts to the coral reefs and offshore surf site have yet to be adequately addressed. Coastal Pollution Point Sources: In areas near offshore sewage outfalls, long-term studies show little or no effect of water chemistry on coral communities. This was not the case in the period from approximately the 1950s to 1970s when discharge of poorly treated sewage on shallow offshore areas of Sand Island (Dollar, 1979) and in Kaneohe Bay resulted in significant damage to coral reef communities (Smith et al., 1981). In the 1980s, Hawaii took significant action to improve coastal water quality by removing most wastewater outfalls from bays and shallow waters. Moving sewage outfalls to deep offshore waters (~40-75 m) has allowed significant recovery to the previously stressed areas (Dollar and Grigg, 2003). Another reversal of impacts from point source discharges has occurred on the Hamakua Coast of the island of Hawaii, where reef communities that were severely damaged by point source discharges of sugarcane processing waste have recovered following the closure of sugar plantations (S. Dollar, pers. obs.).

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Seven major wastewater treatment Table 9.1. Wastewater treatment plants that discharge to Hawaii’s coastal waters. plants discharge to the coastal ocean Source: U.S. EPA. in Hawaii (Table 9.1). All but three LEVEL OF TREATMENT of these discharge through deepwaDeepwater Discharges (>40 m) ter outfalls (>40 m). Under terms of Sand Island, Oahu Advanced primary a consent decree filed in November Honouliuli, Oahu Advanced primary 1991 with the Federal district court Waianae, Oahu Secondary for violations of the Federal Clean Kailua, Oahu Secondary Water Act, the City and County of HoHilo, Hawaii Secondary nolulu agreed to provide $8 million for Shallow Water Discharges (10%), warranting further experimental investigation and more detailed observations in the future. Environmental variables that explained changes in coral cover included rugosity, mean wave height, and watershed area (Jokiel et al., 2004). page 249



Figure 9.24. Results of CRAMP monitoring efforts since 1999 show trends in coral cover at sites across the state. Shallow sites (3 m) are shown in light pink and deeper sites (8 m) are shown in dark pink. Source: Jokiel et al., 2004.

• Stations with higher rugosity or more topographical complexity experienced greater declines in coral cover. • In contrast, stations exposed to higher mean wave height or situated adjacent to larger watersheds had significant increases in coral cover. Turgeon et al. (2002) reported “the consensus of many ecologists is that, with a few exceptions, the health of the near-shore reefs around the MHI remains relatively good.” On the other hand, some researchers, local fishers and recreational divers with long-term experience observe that reefs in many areas of Hawaii have declined over past decades. For example, Jokiel and Cox (1996) have noted degradation of Hawaiian reefs due to human population growth, urbanization, and coastal development. Absence of the catastrophic short-term reef declines that have been noted in other geographic areas (e.g., Hughes, 1994) can lead to the impression that Hawaiian reefs are in good condition. Slow rates of decline, however, will eventually reFigure 9.25. Trends in coral cover between 1999-2002 at CRAMP sites show a de- sult in severely degraded reefs. The cline for the islands of Oahu, Molokai, and Maui. Source: Jokiel et al., 2004. spatial patterns and temporal change page 250

of coral reef community structure in relation to human population that were observed in this study suggest that the rapidly growing human population of Hawaii may be having a negative effect on the reefs. Long-term monitoring will be required to differentiate the observed short-term declines in coral cover from natural oscillations (Done, 1992) in Hawaiian reef community structure (Hughes and Connell, 1999). Long-Term Monitoring at Selected Sites Selected sites throughout Hawaii have been monitored over a longer time period (>10 years) and were incorporated into CRAMP to extend the historical perspective including one site on Kauai, five on Oahu, and two on Maui (Table 9.8). Puako, Hawaii, which is not part of CRAMP, is included because it has also been surveyed for over 10 years. Coral cover at several stations within each site has been surveyed sporadically over the years (Table 9.8). Different methods have been used but studies that have compared methods produced similar results (e.g., Brown, 2004). For comparative purposes, only transects or quadrats that sampled the same spatial habitat as CRAMP were utilized. The selected sites may not be representative of wave exposed reefs around Hawaii because six of the nine sites (12 of 15 stations) are located in protected embayments. Sites such as Hanauma Bay, Honolua Bay, and Olowalu, however, are high human use areas and changes at these reefs have important management implications. In addition, long-term data sets on coral cover are uncommon and provide benchmarks for future comparisons. Temporal results for all of the sites are listed in Table 9.8.



Table 9.8. Average percent coral cover at selected sites that have been surveyed at time periods spanning 10 or more years. Overall percent change (∆) from the initial survey to the last survey is shown in the last column. Data sources for each station are listed below. * indicates locations within Kaneohe Bay.

ISLAND SITE Kauai Oahu

Hanalei Bay

3m1,2

15

16 26

17 17 2

8m

20

28 30

26 36 16

1,2

Kahe Point

3m2,3

19 19 15 16 16 18 22 20 18 17 12 10 5 5 4 5 9 7 12 13 15 15

-4

Pili o Kahe

3m2,3

19 12 10 10 9 8 10 11 12 18 17 16 14 11 9 8 8 7 9 7 10 11

-8

Kaalaea*

2m2,4,5

79

62 51 49 67 59 -33

7

11

9

3 2 4 3 3 -4

64

62

36 23 18 24 22 -11

8m2,4,5

1

15

2

8 7 7 5 7 6

Moku o Loe*

2m2,4,5

6

45

21

30 20 16 13 14 9

9m2,4,5

0

4

3

Hanauma Bay

3m2,6,7

28

47 28

28

28 33 24 26

22

-6

10m2,6,7

38

40 36

33

32 25 27 27

22

-15

41 35 28 28 24 15 17 15 14

-25

42 42 38 33 28 21 27 23 24

-19

32 30 23 30 30 23 25 22 23

-8

55 56 47 57 51 55 54 53 51

-4

2,4,5

North 3m 2,7,8,9,10,11

South 3m 2,7,8,9,10,11

Olowalu Hawaii

82

33

Honolua Bay

8m

92

2m2,4,5

Heeia*

Maui

STATION 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 ∆

Puako

39

23

43

36

8 7 6 4 9 9

51 56

3m2,10,12

31

8m2,10,12 3m

7,13

10m7,13

DATA SOURCES 1 Friedlander et al., 1997 2 Jokiel et al., 2004 3 Coles, 1998 4 Maragos, 1972 5 Hunter and Evans, 1995 6 Anderson, 1978 7 Hunter, 1999

8 9 10 11 12 13

66

42 42 43

47

58 60

-5

63

46 41 43

44

59 45

-18

Environmental Consultants, 1974 Torricer et al., 1979 Brown, 1999 Dollar and Grigg, 2004 Ambrose et al., 1988 Hayes et al., 1982

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Statewide Trends Hanalei Bay, Kauai Total coral cover at the 3-m station appears to be holding steady while total coral cover at the 8-m station has increased nearly 17% (84% relative increase). Kahe Point and Pili o Kahe, Oahu Both stations appear to be undergoing 12-13 year oscillations in total coral cover. The temporal patterns, however, do not coincide. Pili o Kahe reached a low point in coral cover in 1986 (8% ± 1% SE) and 1998 (7% ± 2% SE). In contrast, coral cover at Kahe Point declined in 1983 to 15% ± 2% SE and to 4% ± 1% SE in 1995. Kaalaea, Kaneohe Bay, Oahu The Kaalaea 2-m station has experienced a decline in total coral cover of 34% (36% relative decrease). Total coral cover at the 8-m station was higher in 1983 (7%) compared to 1971 (11%-68% relative increase), but then decreased to 3% (72% relative decrease) by 2003. Much of the decrease in coral cover was attributed to slumping of the reef slope (Jokiel et al., 2004). Heeia, Kaneohe Bay, Oahu The Heeia 2-m station followed a similar pattern to the Kaalaea 8-m station with higher total coral cover in 1983 (64%) compared to 1971 (33%-93% relative increase). By 2003, coral cover declined to 22% (66% relative decrease). The percent cover at the 8-m station appears to have increased since 1971, but has fluctuated in the interim. Moku o Loe, Kaneohe Bay, Oahu At Moku o Loe, coral cover increased in 1983 at the 2-m station by 39% (680% relative increase), but subsequently declined to 14% in 2003 (68% relative decrease). In comparison, coral cover at the 9-m station has slowly increased from 0% to almost 9% since 1971. Hanauma Bay, Oahu The Hanauma Bay 3-m station experienced an 18% increase (65% relative increase) in coral cover from 1976 to 1992. Subsequently, coral cover steadily declined to 22% (25% absolute decline, 53% relative) by 2002. The Hanauma Bay 10-m station had similar total coral cover values in 1976 (38%) and 1992 (40%), and then declined to 22% (18% absolute, 45% relative decrease) by 2002. Honolua Bay, Maui The 3-m stations on the north and south reefs appeared to be relatively stable from 1974 until 1994. From 1994 to 1998, coral cover declined from 41% to 14% (66% relative decrease) at the north station and from 43% to 24% (44% relative decrease) at the south station. Since 1999, coral cover has stabilized at both stations. Olowalu, Maui The Olowalu 3-m station showed a gradual decline in coral cover of 8% (26% relative decrease) since 1998. In contrast, the Olowalu 8-m station has remained relatively stable from 1994 to 2002, with total coral cover between 51-55%. Puako, Hawaii Total coral cover appears to be increasing at the Puako 3-m station (18% absolute increase, 43% relative increase) to 1982 levels, after an initial drop of 23% (36% relative decline) from 1982 to 1991. In comparison, total coral cover at the 10-m station was 63% in 1982 and only 46% in 1991. This was a 17% decline (27% relative decline) that increased to 58% (12% absolute increase, 27% relative increase) in 1997 and subsequently decreased to 45% in 1998. The increase in coral cover at the 10-m stations was mirrored at the 3-m station until 1998 when trends diverged at the two stations. Summary The long-term trends at the selected sites show that the majority of the stations (13 out of 18) have declined since the first survey. Several of these stations (e.g., Kahe Point 3-m station) have experienced minor decreases in coral cover that can be explained by measurement error and therefore are not ecologically relevant. Explanations for the major declines (>10%) include reef slumping (e.g., Kaalaea; Jokiel et al., 2004)

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and sedimentation (e.g., Honolua Bay; Dollar and Grigg, 2004). Dollar and Grigg (2004) have suggested that embayments with restricted circulation, such as many of the sites previously listed, are more susceptible to anthropogenic stresses. Intermittent sampling, however, confounds most of the monitoring studies. As shown in the Kahe data, oscillations in coral cover may be occurring that are not detected from the sporadic sampling at the other stations. Therefore, inferring that the selected sites are in fact declining should be interpreted with caution. At present, however, these data sets are the best indicators of long-term trends in Hawaiian coral reefs.

ASSOCIATED BIOLOGICAL COMMUNITIES West Hawaii Aquariumfish Project In response to longstanding concern and controversy over marine aquarium collecting in West Hawaii, the nineteenth Hawaiian legislature passed Act 306 in 1998 which established the West Hawaii Regional Fisheries Management Area in the nearshore waters from Upolu Point (North Kohala) to Ka Lae (Kau). One of the primary goals of the legislation was to improve management of fish resources by designating a minimum of 30% of the West Hawaii coastline as FRAs where aquarium fish collecting was prohibited.



Methods Study sites were established in early 1999 in six existing reference areas, eight open areas adjacent to FRAs, and all nine FRAs. Using stainless-steel bolts cemented into the bottom, four permanent 25-m transects were established in a H-shaped pattern at each of the study sites. Fish densities were estimated by a pair of divers who conducted visual surveys along each transect. Divers swam side by side and surveyed a column 2 m wide (4 m total width). On the outward-bound leg, larger planktivores and wide-ranging fishes were recorded. On the return leg, fishes closely associated with the bottom, new recruits, and fishes hiding in cracks and crevices were recorded. Power analysis of preliminary fish transect data indicated that the observational design would detect 10–160% changes in the abundance of the principal targeted aquarium fishes in West Hawaii during the first year using reasonable error rates (α=β=0.10). Results and Discussion Over the course of the four years of the WHAP study, overall aquarium fish abundance (top 10 species) has been increasing (linear regression, p